+ add sample

BUG=angleproject:2306

Change-Id: Ie0c391618ec2b771cc99b96db02b9008a86272b9
Reviewed-on: https://chromium-review.googlesource.com/1079992
Commit-Queue: Lingfeng Yang <lfy@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>